Refactor exit_code implementation

cmd2.Cmd.cmdloop() now returns self.exit_code which should be an integer

Also:
- Refactored examples to call sys.exit(app.cmdloop()) in their __main__
- Running transcript tests now sets the exit_code accordingly based on success/failure
- Updated CHANGELOG
- Updated README
- Updated Sphinx docs
- Added unit test for case when transcript test fails

1 files changed, 2 insertions, 1 deletions

diff --git a/examples/python_scripting.py b/examples/python_scripting.py
index 7847b8b6..da7d0f6a 100755
--- a/examples/python_scripting.py
+++ b/examples/python_scripting.py
@@ -117,5 +117,6 @@ class CmdLineApp(cmd2.Cmd):
 
 
 if __name__ == '__main__':
+    import sys
     c = CmdLineApp()
-    c.cmdloop()
+    sys.exit(c.cmdloop())